[交流] 【求助成功】VASP中，如何固定磁矩做结构优化 已有6人参与

Originally posted by Prettyswan at 2010-07-08 16:00:03:
官方指南上写道：

一般来说，VASP是默认不考虑电子自旋改变的可能，就是说默认的就是固定了自旋磁矩了的。

[ Last edited by Prettyswan on 2010-7-8 at 16:56 ]

6.35   NUPDOWN
NUPDOWN = difference between number of electrons in up and down spin component
Allows calculations for a specific spin multiplet, i.e. the the difference of the number of electrons in the up and down spin component will be kept fixed to the specified value. There is a word of caution required: If NUPDOWN is set in the INCAR file the initial moment for the charge density should be the same. Otherwise convergence can slow down. When starting from atomic charge density (ICHARG=2), VASP will try to do this automatically by setting MAGMOM to NUPDOWN/NIONS. The user can of course overwrite this default by specifying a different MAGMOM (which should still result in the correct total moment). If one starts from the wavefunctions, the initial moment will be always correct, because VASP will “push” the required number of electrons from the down to the up component. If starting from a chargedensity supplied in the CHGCAR file (ICHARG=1), the initial moment is usually incorrect!
If no value is set (or NUPDOWN=-1) a full relaxation will be performed. This is also the default.